Thomas forsaith



(No Model.)

T. FORSAITH. SAW FOR CUTTING TENONS. No. 400,906. Patented Apr. 9, 1889.

W/TNESSES INVENTOR.

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UNITED STATES PATENT OFFICE.

THOMAS FORSAITH, OF ADELAIDE, SOUTH AUSTRALIA.

SAW FOR CUTTING TENON S.

SPECIFICATION forming part of Letters Patent No. 400,906, dated April 9, 1889. Application filed March 1, 1888- Serial No. 265,883. (No model.) Patented in England January 11, 1888, No. 457.

To all whom it may concern.-

7 Be it known that I, THOMAS FORSAITH, machinist, a subject of the Queen of Great Britain, and a resident of Adelaide, in the Province of South Australia, have invented a Saw for Cutting Tenons, (for which I have obtained a patent in Great Britain, No. 457, bearing date January 11, 1888,) of which the following is a full, clear, and exact description.

My invention relates to handsaws for cutting tenons in wood.

It has been the practice in cutting tenons to use a saw having a single blade, and, after making the cut 011 one side, care and skill have been necessary in making the second cut parallel to the first. Besides, when a number of tenons have been required to be cut of the same size, careful measurement has been necessary.

The object of my invention is to avoid these difficulties by constructing a tenon-saw with two blades attached to aframe and so arranged that they can be set at any desired distance apart in order to cut tenons of different widths. By the use of my invention the two sides of the tenon are always parallel, and, once the saw-blades are fixed, any number of tenons can be cut of the same width.

By reference to the accompanying drawings it will be seen that Figure 1 is a side view, and Fig. 2 an end view, of a double tenon-saw embodying my invention. Figs. 3 and 4 are detail views of a clip for adjusting the distance between the saw-blades.

A A, Figs. 1 and 2, are tenon-saw blades; B, front piece; 0, adjusting screws and nuts; D, back piece; E, main beam; F, strainingbar; G, handle; H, Figs. 3 and 4, adjustingclips.

The front piece, B, consists of a flat piece of metal or other suitable material, to the parallel sides of the lower end of which the saws are secured by the adj Listing-screw O. The back piece, D, consists of a further piece of similar metal firmly secured to a wooden handle in the usual manner and provided with a similar screw-nut, C. To the back piece, D, is forged the main beam E, consisting of a round or fiat bar provided at its outer extremity with a double joint, by means of which it is secured to the front piece, B, in such manner as will allow of the latter oscillating. The straining-rod F passes through B and D, and is provided with a head and screw-nut, or it may be in two pieces, connected in the center with a screw-swivel in the ordinary manner. The adj usting-clips H are made in pairs of various thicknesses, preferably corresponding with the sizes of the chisels of mortising-machines, and are constructed to fit accurately upon the front and back pieces, B and D. Each clip is made in the shape of a fork, of a width correspond. ing with the width of the end of the sawblade and of a length sufficient to pass beyond the point of the fasteningscrew G, being perforated to admit said screw.

WVhen it is desired to alter the width of the tenon to be cut, the screw-nuts C are loosened and adjusting-clips H, of the required thickness, placed upon B and D. The screws 0 are then replaced and the saws brought to the desired tension by means of the strainingbar F.

It will be readily perceived that, the two saws being set parallel, the sides of the tenon must always be cut equally so, and that once the saws are set to any required distance apart any number of tenons can be cut of an exactly similar width.

The saws and frame may be made of any convenient size and of any suitable material.

What I claim as new, and desire to secure by Letters Patent, is-

The adjusting-clips H, in combination with the front and back pieces, B and D, the main bar E, the straining-rod F, the fasteningscrews 0, and the saw-blades, substantially as shown and described.

In witness whereof I have hereunto signed my name in the presence of two subscribing witnesses.

THOS. FORSAITH.

Witnesses:

THOMAS CORIN HOLLAND,

Public Notary, Adelaide, S. A. JOHN ALFRED NoRTHMoRE, J r.,

Articlerl Clerk, Adelaide, S. A. 

